diff --git a/block/ioctl.c b/block/ioctl.c
index a5f672a..64e7c67 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -30,7 +30,7 @@
 	if (bdev != bdev->bd_contains)
 		return -EINVAL;
 	partno = p.pno;
-	if (partno <= 0 || partno > disk_max_parts(disk))
+	if (partno <= 0 || partno >= disk_max_parts(disk))
 		return -EINVAL;
 	switch (a.op) {
 		case BLKPG_ADD_PARTITION:
@@ -102,7 +102,7 @@
 	struct gendisk *disk = bdev->bd_disk;
 	int res;
 
-	if (!disk_max_parts(disk) || bdev != bdev->bd_contains)
+	if (!disk_partitionable(disk) || bdev != bdev->bd_contains)
 		return -EINVAL;
 	if (!capable(CAP_SYS_ADMIN))
 		return -EACCES;